pc not starting after motherboard and psu change

[Eskil28]

I changed my psu and motherboatd due to them being broken and now when I changed when I plug in the psu and turn the start button to on my keyboard and mouse lights up and when I press the start button it doesn’t start so the thing is the pc reacts to when I flip the switch to on on the psu but it doesn’t want to start. The power switch lights up aswell. 
what can the problem be

5700xt 

Ryzen 5 3600

gigabyte A520M Ds3H

Msi mpg a650gf 650W

Corsair venegrqnce 2x8 gb 3600 MHz 

 

Im linking a photo of the motherboatd and ignore the cables at the bottom they are spares.